Problem: Rewrite ${((3^{-10})(5^{-10}))^{-9}}$ in the form ${3^n \times 5^m}$.
Solution: ${ ((3^{-10})(5^{-10}))^{-9} = (3^{(-10)(-9)})(5^{(-10)(-9)})} $ ${\hphantom{ ((3^{-10})(5^{-10}))^{-9}} = 3^{90} \times 5^{90}} $